物理化学学报 >> 1990, Vol. 6 >> Issue (04): 430-436.doi: 10.3866/PKU.WHXB19900409

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DHDECMP萃取硝酸铀酰的热力学研究

杨学先   

  1. 中国农业科学院原子能利用研究所，北京
  • 收稿日期:1989-04-19 修回日期:1989-09-24 发布日期:1990-08-15
  • 通讯作者: 杨学先

The Thermodynamics of Extraction of Uranyl Nitrate by Bidentate Organophosphorus Extractant Dhdecmp

Yang Xue-Xian   

  1. Institute for Application of Atomic Energy, CAAS, Beijing
  • Received:1989-04-19 Revised:1989-09-24 Published:1990-08-15
  • Contact: Yang Xue-Xian

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摘要： 在288—343 K的温度范围内, 研究了不同浓度的DHDECMP(溶于DEB)自0.25—5摩尔硝酸介质中萃取铀(Ⅵ)的分配比与温度的关系. 据此, 用外推法首次获得了该萃取体系离子强度为零时的萃取热力学参数: K_t(1.15±0.10)×10~3, △H_t~0=27.5 kJ·mol~(-1), △G~0=-17.5 kJ·mol~(-1), △S°=33.5 J·mol~(-1)K~(-1).

Abstract: The distribution data for U(Ⅵ) from 0.25-5 mol·L~(-1) nitric acid media with 1--40 V% DHDECMP (dihexyl N,N-diethyl carbamoylmethyl phosphonate) in DEB (diethyl benzene) were determined in the temperature range 288--343 K. From the variation of the distribution ratios with temperature the enthalpy changes associated with the extraction were evaluated. Using extrapolation technique the thermodynamic value of the enthalpy (ΔH°_t) for zero ionic strength was obtained to be -27.5 kJ·mol~(-1). The thermodynamic equilibrium constant (K_t), free energy (ΔG°) and entropy changes (ΔS°) were calculated at 25 ℃ to be 1.15×10~3, -17.5 kJ·mol~(-1) and -33.5 J·mol~(-1)·K~(-1), respectively.